Weight on bit indicating and drilling control signaling apparatus



March 1, 1955 A. L. SELJOS ET AL WEIGHT ON BIT INDICATING AND DRILLING CONTROL SIGNALING APPARATUS Filed Aug. 17, 1951 2 Sheets-Sheet l i To Automatic Control Converting Meons 7 Regulator Air Pressure INVENTOR.

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March 1, 1955 A. L.. SELJOS ET AL WEIGHT ON BIT INDICATING AND DRILLING CONTROL SIGNALING APPARATUS Filed Aug. 17, 1951 2 Sheets-Sheet 2 Algernon 5. Badger. y Arthur L. Se/jos,

United States Patent WEIGHT ON BIT INDICATING AND DRILLING CONTROL SIGNALING APPARATUS Arthur L. Seljos and Algernon S. Badger, Houston, Tex.,

assignors, by mesne assignments, to Standard Oil Development Company, Elizabeth, N. .L, a corporation of Delaware Application August 17, 1951, Serial No. 242,301

5 Claims. (Cl. 73--151) The present invention is directed to a weight on bit indicating and a drilling control signalling apparatus. More particularly, the invention is directed to apparatus for indicating the weight on bit directly while delivering a signal to automatic control for drilling operations responsive to the weight on the bit.

The present invention may be briefly described as a device for indicating the weight on bit and drilling control signalling apparatus which comprises means adapted to be attached to a line of a well drilling rig and adapted to deliver a pressure signal responsive to tension exerted on said line. The pressure signal is delivered to a converting means which is operatively connected to the pressure signal means. The converting means includes first, second and third pressure responsive means and a valve operatively connected to the third pressure responsive means, the first pressure responsive means being responsive to the changes in the pressure signal delivered by the pressure signalling means while the second pressure responsive means is responsive to a pressure diflerent from that delivered by the pressure signalling means. The third pressure responsive means is adapted to open and close the valve and to deliver fluid therethrough from a source of fluid pressure to a conduit connected to an outlet of the valve. A pressure indicating means is operatively connected to the pressure converting means for indicating the weight on a drilling bit attached to the line. The pressure indicating means may be connected to the conduit connected to the outlet of the pilot valve, the pressure signal from the device being directed through the conduit to automatic drilling control mechanism for actuation thereof.

The present invention will be further described and illustrated by reference to the drawing in which Fig. 1 is a schematic illustration of the several elements of our invention, and

Fig. 2 is a sectional view of the pressure converting means making up an element of the combination.

Referring now to the drawing, Figs. 1 and 2, numeral 11 designates a wire line, such as a live or dead line, of a well drilling rig which is operatively connected to a drilling weight responsive device 12. Drilling rig responsive device 12 may be a load or weight responsive means, such as described in the patent to Shimek, 2,013,810, issued September 10, 1935, or it may be a tension or responsive means, such as described in the patent to Martin, 1,872,087, dated August 16, 1932. Other equivalent devices, such as are well known to the prior art, may be used as the means to be attached to the line of a well drilling rig so long as it will deliver a pressure signal responsive to tension exerted on a wire line to which the pressure signalling means may be attached. The drilling weight responsive device, such as 12, is operatively connected by a line or conduit 13 to a pressure converting means generally indicated by numeral 14. Pressure converting means embodies first, second and third pressure responsive means and a valve. The first pressure responsive means is illustrated by a diaphragm A while the second pressure responsive means is indicated by a diaphragm B. A third pressure responsive means is designated as a diaphragm C for the purposes of this illustration. A valve such as a pilot valve 15 which is indicated schematically in Fig. l is operatively connected to diaphragm C by the element generally indicated as 16. An adjusting pressure is delivered against the diaphragm B through a conduit 17 containing a pressure regulator valve 18 which is connected by conduit 19 to a source of fluid pressure such as air. A branch line 20 connects to line 19 and delivers air to valve 15 and thence, controlled by valve 15, to conduit 21 and to pressure indicating means such as a pressure gauge 22 connected to line 21 by conduit 23. The conduit 21 is adapted to be connected to an automatic drilling control mechanism and to deliver a pressure signal thereto.

Referring now specifically to Fig. 2, the pressure converting means 14 has arranged therein diaphragms A, B and C. The pressure converting means includes a housing 30 which encloses a first chamber 31 and a second chamber 32. The housing 30 is provided with a first plate 33 which defines an inlet 34 which is adapted to be connected to conduit 13. The housing 30 is provided with a second cover plate 35 which defines an inlet 36 which is adapted to be connected to line 17. The cover plate 33 is bolted to housing 30 by threaded bolts 37 and the cover plate 35 is bolted to housing 30 by threaded bolts 38. Arranged between the diaphragms A and B are plates 40 and 41. Plate 40 is above diaphragm A and fits snugly thereagainst while plate 41 is below diaphragm B and fits snugly thereagainst and against plate 40. Above the diaphragm B and the plate 41 is a third plate 42. The three plates are connected to each other by inset threaded bolts 43 and by pin 44.

Connected to the cover plate 35 by threaded bolts 50 is a housing 51 enclosing a third chamber 52 in which is arranged diaphragm C. Diaphragm C is connected by an actuating means 16 to a valve generally indicated by the numeral 60 which is provided with an inlet 61 which is connected to line 20 and an outlet 62 which is connected to line 21 and to pressure gauge 22.

The element 16 is provided with a passageway 63 which terminates at the lower end of element 16 into ports 64 which communicate with chamber 52 and thence by port 65 with the atmosphere. The valve 60 includes a valve mechanism 66 arranged in a chamber 67 of valve 60. The element 66 is sealed in the chamber 67 by O-rings 68 and 69 and encloses a compression member, such as spring 70 arranged in the internal chamber 71 of valve mechanism 66. The spring 70 bears against a spherical seating member 72 which is connected by a longitudinal member 73 to a second seating member 74. The first spherical seating member 72 fits on the lower part of the member 66 while the seating member 74 fits on the seating member 75 defined by element 16. The element 72 serves to open and close a vertical passage 72a in valve mechanism 66 and allows communication between inlet 61 and outlet 62 through passage 72a and 62a while the spherical seating member 74 serves to open and close the passageway 63 of element 16 bearing against the lower end of seating member 74; fitting into a recess 77 of element 16 is a compression means such as a coil spring 78 which bears against the mechanism 66 and the element 16. Outlet 62 is fluidly connected to the lower portion of chamber 67 below valve mechanism 66 by a passageway 62a.

The diaphragm C is snugly held in chamber 52 by a shoulder 79 of element 16 and a plate 80 held in place by nut 81, which is threadably attached to element 16. The element 16 bears against a pin which is slidably fitted into the cover plate 35 of the housing 30. This pin is sealed with an O-ring 91. It will be noted that the chamber 31 between the diaphragms A and B is vented to the atmosphere by a port 92. It will be further noted that the chamber 31 is provided with a stop 93 to limit the travel of plate 41.

The valve 60 is provided with an adjusting screw which bears against the valve mechanism 66. The ad justing bolt 100 is held in place by the lock-nut 101. The valve 60 is attached to the housing 51 by threaded bolts 102.

The apparatus of the present invention functions in the following manner:

Assuming that the converting means 14 has no pressure exerted on either diaphragms A, B, or C, at the beginning, the apparatus is adjusted for use by admitting a pressure, proportional to the total weight exerted on line 11, against diaphragm A through inlet 34. This causes movement of diaphragm A which serves to open the pilot valve 15 admitting air through port 61, port 76, and passageway 7211 against diaphragm C and delivering air through port 62a and 62. In this example the areas of diaphragms A and B are equal. The signal pressure from weight responsive means 12, as shown in the example which follows, is several times greater than the pressure of the air admitted from the supply air through line 20 to port 61. Therefore, the weight on bit gauge 22 may be considered as a vernier gauge for the total weight, including weight on bit, exerted on line 11. The maximum forces exerted on diaphragm A by the signal pressure are greater than the maximum forces exerted on diaphragm C. To balance the converting means 14, pressure is then admitted to diaphragm B through inlet 36 from conduit 17 and regulator 18 until the forces on B and C are equal to the forces exerted on A. Then the weight on bit gauge 22 reads zero but actually is 95 pougds per square inch. Any change then reflects weight The weight on bit gauge is calibrated so that a decrease in pressure on the gauge indicates an increase in bit weight. With the converting means 14 in a balanced state, the inlet and outlet valves are both closed. When the total weight on line 11 decreases, the pressure transmitted through conduit 13 decreases. Then the force exerted by diaphragm A is less than the force exerted by diaphragms B and C, causing the pilot valve 15 to exhaust air pressure from above diaphragm C and from conduit 21 through port 62 until the assembly is again in balance. The lower pressure on diaphragm C is then read on gauge 22 as the actual weight on bit.

If the weight on bit should decrease, an increase in pressure from conduit 13 to diaphragm A would result with the force on A being greater than diaphragms B and C; the pilot valve 15 would then admit air through port 61 until enough pressure was admitted to diaphragm C to put it back in a balanced state with neither air being admitted nor exhuasted.

Thus, the converting means 14 serves to balance out the weight exerted on line 11 other than weight on bit and allows the weight on bit to be read directly on gauge 22.

Thus a drilling weight pressure signal is exerted on diaphragm A from the drilling rig weight responsive means generally designated as 12. A regulated air pressure is delivered to diaphragm B from regulator 18 by line 17. Air pressure is delivered by conduit 20 to inlet 61 of the pressure converting means 14. The diaphragms A, B and C are related so that the pressure on A times the area of the diaphragm A equals the pressure on diaphragm B times the area of diaphragm B plus the pressure on diaphragm C times the area of diaphragm C. The converting means 14 has the characteristic, by the selection of the areas of the three diaphragms and their relationship to each other to supply pressure which is delivered by conduit 21 which may range from to the maximum pressure delivered by conduit 20, the fluctuations being indicative of the weight on bit and responsive to the pressure signal delivered by line 13.

Referring to Fig. 2 especially, it will be seen that a pressure signal is delivered through inlet 34 to diaphragm A which causes this diaphragm to flex upwardly. At the same time an adjusting pressure is delivered to diaphragm B through inlet 36 by line 17. This causes the diaphragm B to flex downwardly. The net result of the signalling pressure operating against the adjusting pressure is that the plates 40, 41 and 42 are caused to move in an upward or downward direction depending on whether the pressure signal through line 13 is increasing or decreasing. An increase in weight on bit results in a decrease of signalling pressure and a decrease in weight on bit results in an increase in signalling pressure in this device. Assuming that the pressure is such that the net effect is the flexing upward of the plates, 40, 41 and 42, this would cause the pin 90 to move upward against the valve operating element 16 connected to the diaphragm C. In the meanwhile, however, fluid pressure is being delivered by line 20 to inlet 61 and the spherical element 72 is moved off its seat on valve mechanism 66 and causes delivery of air through outlet 62 to conduit 21. However, as the element 72 moves 01f its seat, this allows the air pressure introduced by inlet 61 to be exerted also against the diaphragm C which causes flexing of diaphragm C in a downward direction; thus a decrease in weight on bit results in an increase of signal pressure and will cause the pilot valve to admit air until the device is in balance allowing the direct weight on bit to remain constant on the pressure indicating means 22 and delivering a constant signal to the automatic drilling control mechanism, not shown. When the apparatus gets out of balance by a decrease in the signal pressure the diaphragm C will flex downward to the point where the spherical member 74 will be unseated by moving off seat 75 causing exhaustion of air from port 62 and the space above diaphragm C through to passageway 63 and then by way (32 port 64 to chamber 52 and to the atmosphere by port The direct weight on bit gauge 22 has a maximum reading equal to the pressure source to which line 19 is connected. In order to be able to cover the desired total weight range with a lower supply of pressure, diaphragm B has an area larger than the area of diaphragm A. Diaphragms A and C have equal areas. Thus the pressure on diaphragm A times the area of diaphragm A equals the pressure of diaphragm B times the area of diaphragm B plus the area of diaphragm C times the area of diaphragm C.

In operating, the zero weight pressure is adjusted by regulator 18 to make the gauge 22 read zero weight, that is about lbs./sq. in. when the bit is off the bottom. As the weight responsive pressure decreases with increasing weight on bit the weight on bit pressure at gauge 22 decreases in proportion. The gauge first is calibrated to read bit weight directly in pounds. It may be desirable to make the zero weight 90% of the whole scale so that the weight otf bit may be read to indicate 10% full scale for tight hole indicating, fishing, etc.

It is to be understood that it is possible to vary the ratios of the three diaphragms to each other as may be desired to obtain most efficient utilization of our invention.

Example In an actual commercial operation a signal from a load or weight responsive means of the type illustrated amounting to 440 lbs/sq. in. was transmitted to the equivalent of conduit 13 against the equivalent of diaphragm A in Figs. 1 and 2 with the bit ofl? bottom. At the same time an adjusting pressure of 70 lbs/sq. in. was transmitted to the equivalent of diaphragm B, bringing the equivalent of gauge 22 to zero. Pressure in line 21 was then 90 pounds per square inch. The drill string was then lowered to place the bit on bottom and the load or weight responsive means then transmitted a signal of 400 pounds per square inch through conduit 13, the adjusting pressure remaining unchanged at 70 pounds per square inch. The net effect of the signalling pressures against the adjusting pressure were transmitted through the equivalent of three plates 40, 41 and 42 to the valve 15 through the equivalent of diaphragm C. During time of these signals air at lbs/sq. in. pressure was introduced to the inlet of the equivalent of valve 15 by a conduit corresponding to line 20. The decrease in the signal of 40 pounds per square inch caused by lowering the bit on bottom showed an increase in weight on bit on gauge 22. Thus the effect of the adjustment pressure against the signalling pressure and the air introduced by line 20 caused air to be delivered through line 21 to the gauge 22 and to the automatic drilling control mechanism, not shown, at a pressure of 50 lbs/sq. in.; by suitably calibrating the gauge 22, this pressure was made to show the direct weight on bit on gauge 22 at 20,000 pounds. The procedure is repeated when the weight on the drill string ofi bottom is changed and at such time the adjusting pressure may likewise be changed.

The nature and objects of the present invention having been completely described and illustrated, what we wish to claim as new and useful and to secure by Letters Patent is:

1. A weight on bit device which comprises, in combination, means adapted to be attached to a line of a well drilling rig and adapted to deliver a pressure signal responsive to tension exerted on said line, means for converting said pressure signal including first, second, and third pressure responsive means and a valve operatively connected to said third pressure responsive means, means operably connecting said first pressure responsive means to said pressure signalling means, said first pressure responsive means being responsive to changes in the pressure signal delivered by said pressure signalling means, means operably connecting said second pressure responsive means to a source of pre-set pressure different from that delivered by the pressure signalling means, said second pressure responsive means being responsive to said pre-set pressure and said pre-set pressure opposing the signal pressure on said first pressure responsive means, means for delivering fluid under pressure to said valve and to said third pressure responsive means, and pressure indicating means operatively connected to said valve to receive said fluid for indicating the weight on a drilling bit attached to said line, said third pressure responsive means being adapted to open said valve and receive said fluid under pressure to oppose the signal pressure and to close said valve and exhaust said fluid from said third pressure responsive means and said pressure indicating means.

2. A weight on bit device which comprises, in combination, means adapted to be attached to a line of a well drilling rig and adapted to deliver a pressure signal responsive to tension exerted on said line, means for converting said pressure signal including first, second, and third diaphragms and a pilot valve operatively connected to said third diaphragm, means operatively connecting said first diaphragm to said pressure signalling means, said first diaphragm being responsive to changes in the pressure signal delivered by said pressure signalling means, means operatively connecting said second diaphragm to a source of pre-set pressure different from that delivered by the pressure signalling means, said second diaphragm being responsive to said pre-set pressure and said pre-set pressure opposing the signal pressure on said first draphragm, means for delivering fluid under pressure to said valve and to said third diaphragm, and pressure indicating means operatively connected to said valve to receive said fluid for indicating the weight on a drilling bit attached to said line, said third diaphragm being adapted to open said valve and receive said fluid under pressure to oppose the signal pressure and to close said valve and exhaust said fluid from said third diaphragm and said pressure indicating means.

3. A weight on bit device which comprises, in combination, means adapted to be attached to a line of a well drilling rig and adapted to deliver a pressure signal responsive to tension exerted on said line, means for converting said pressure signal including first, second and third diaphragms, a first conduit operatively connecting said first diaphragm with said pressure signalling means, a pilot valve having an inlet and an outlet operatively connected to said third diaphragm, a second conduit connected to said outlet of said valve, said first diaphragm being responsive to changes in the pressure signal delivered by said pressure signalling means, a third conduit operably connecting said second diaphragm to a pre-set pressure different from that delivered by said pressure signalling means, said second diaphragm being responsive to said pre-set pressure and said pre-set pressure opposing the signal pressure on said first diaphragm, a fourth conduit for delivering fluid under pressure to the inlet of said valve and to said third diaphragm, and a pressure gauge connected to said second conduit to receive said fluid for indicating the weight on a drilling bit attached to said line, said third diaphragm being adapted to open said valve and receive said fluid under pressure to oppose the signal pressure and to close said valve and exhaust said fluid from said third diaphragm and said pressure gauge, said second conduit being adapted to beconnected to a drilling control mechanism to deliver a pressure signal thereto.

4. A weight on bit device which comprises, in combination, means adapted to be attached to a line of a well drilling rig and adapted to deliver a pressure signal responsive to tension exerted on said line, means for converting said pressure signal including first, second and third pressure responsive means and a valve operably connected to said first pressure responsive means, means operably connecting said first pressure responsive means to said pressure signalling means, said first pressure responsive means being responsive to changes in the pressure signals delivered by said pressure signalling means, means operably connecting said second pressure responsive means to a source of pre-set pressure different from that delivered by the pressure signalling means, said second pressure responsive means being responsive to said pre-set pressure and said pre-set pressure opposing the signal pressure on said first pressure responsive means, means for delivering fluid under pressure to said valve and to said third pressure responsive means, said third pressure responsive means being adapted to receive said fluid pressure to oppose the signal pressure on said first pressure responsive means to open and close said valve and said valve being adapted to deliver fluid to actuate said third pressure responsive means, and means for exhausting fluid from said valve and said fluid pressure responsive means, said delivery and exhaustion of said fluid being an indication of the weight on a bit attached to said line.

5. A weight on bit device which comprises, in combination, means adapted to be attached to a line of a well drilling rig and adapted to deliver a pressure signal responsive to tension exerted on said line, means for converting said pressure signal including first, second and third diaphragms and a valve operably connected to said first diaphragm, means operably connecting said first diaphragm to said pressure signalling means, said first diaphragm being responsive to changes in the pressure signal delivered by said pressure signalling means, means operably connecting said second diaphragm to a source of pre'set pressure different from that delivered by the pressure signalling means, said second diaphragm being responsive to said pre-set pressure and said pre-set pressure opposing the signal pressure on said first diaphragm, means for delivering fluid under pressure to said valve and to said third diaphragm, said third diaphragm being adapted to receive said fluid pressure to oppose the signal pressure on said first diaphragm to open and close said valve, and said valve being adapted to deliver fluid to actuate said third diaphragm, and means for exhausting fluid from said valve and said third diaphragm, said delivery and exhaustion of said fluid being an indication of the weight on a bit attached to said line.

References Cited in the file of this patent UNITED STATES PATENTS 2,099,955 Edwards Nov. 23, 1937 2,304,782 Donaldson Dec. 15, 1942 2,528,883 Hayward Nov. 7, 1950 2,529,883 Otto Nov. 14, 1950 

